1. Field of the Invention
The present invention relates to an image forming apparatus, a method for forming a test pattern, and a computer program product.
2. Description of the Related Art
Image forming apparatuses include printers, facsimiles, copying machines, plotters, and multifunctional peripherals of these. For example, an inkjet recording apparatus and the like are known as image forming apparatuses of liquid discharge recording system which use a recording head(s) including a liquid discharge head(s) (liquid droplet discharge head(s)) for discharging liquid droplets.
Some image forming apparatuses form an image by using recording heads mounted on a reciprocating carriage. Such image forming apparatuses are prone to cause positional deviations of ruled lines between a forward path and a backward path in two-directional printing, and positional deviations due to a physical displacement between a plurality of heads in the case of one-way printing.
As a measure against this, for example, it is known to print a test pattern for adjusting impact positions of liquid droplets on a medium to be recorded and adjust or select droplet discharge timing based on the printed test pattern.
For example, the droplet discharge timing may conventionally be adjusted by printing linear reference patterns and linear adjustment patterns, and inputting a numerical value or the like corresponding to not-deviating ones of the reference patterns and the adjustment patterns by visual observation (Japanese Laid-open Patent Publication No. 10-264485).
When linear patterns are used as the test pattern for positional deviation adjustment as described above, there is a problem of poor visibility if the reference patterns and the adjustment patterns are formed to be simply joined or overlap each other.
Therefore, there is a need for an image forming apparatus and a method for forming a test pattern that are capable of improving the visibility of a test pattern formed by linear patterns.